Gmc Envoy 2004

[Street Legal]

what is the fuel pressure at idle ? is it normal to stay at 55 with the regulator connected to the vaccume line ? the car is stock 2004 gmc envoy and the A/F is 11.5 - 12

[vette_doc]

if your envoy is 4.2L fuel pressure should be 50-57 psi
if your envoy is 4.8L, 5.3L, or 6.0L fuel pressure should be 55-62 psi

[Street Legal]

if your envoy is 4.2L fuel pressure should be 50-57 psi
if your envoy is 4.8L, 5.3L, or 6.0L fuel pressure should be 55-62 psi

the car is really rich at idle i dont know what causing it..i checked every thing
the static fuel pressure KOEO is 55 when i start the car it stays the same why it does not change at idle when the vaccume pulls the diaphram of the regulator shouldn't it go to 45-47 psi ?

[redhotjamedjimi]

thats 55 at idle. most n/a engine are like that to stretch the duty cycles a bit so they fit the smallest injectors possible to save money while not jeopardizing the fuel pump.

and it shouldnt run rich at idle after the trims come into play. unless its after a reflash and theres no long term trims it may be off. be looking for a physical cause maybe plugs, o2 sensors, the post cat one will cause COT even at idle causing a very low afr.